1. Field of the Invention
The present invention relates to transdermal drug delivery device and method, most preferably for the delivery of Vitamin C (ascorbic acid), using a combination of light therapy, heat therapy, cold therapy, and ultrasound therapy.
2. Description of Related Art
The process of wound healing generally encompasses three phases during which the injured tissue is repaired, regenerated, and new tissue is reorganized into a scar. These three phases arc classified as: (a) an inflammation phase which begins from about day 0 to 3 days, (b) a cellular proliferation phase from about 3 to 12 days, and (c) a remodeling phase from about 3 days to about 6 months. In all three phases, antioxidants, such as Vitamin C, play a vital role in the healing process.
In the inflammation phase, inflammatory cells, mostly neutrophils, enter the site of the wound followed by lymphocytes, monocytes, and later macrophages. The neutrophils that are stimulated begin to release proteases and reactive oxygen species into the surrounding medium with potential adverse effects on both the adjacent tissues and the invading microorganisms.
The proliferative phase consists of laying down new granulation tissue, and the formation of new blood vessels in the injured area. The fibroblasts, endothelial cells, and epithelial cells migrate in the wound site. These fibroblasts produce the collagen that is necessary for wound repair. Ascorbic acid is crucial in the formation of collagen. Several studies have demonstrated that ascorbic acid is capable of overcoming the reduced proliferative capacity of elderly dermal fibroblasts, as well as increasing collagen synthesis in elderly cells by similar degrees as in newborn cells even though the basal levels of collagen synthesis arc age dependent. A decrease of ascorbic acid at the injury area will decrease the rate of wound healing.
The final phase of wound healing, which is remodeling, is effected by both the replacement of granulation tissue with collagen and elastin fibers and the devascularization of the granulation tissue. Recent studies have shown that topical application of antioxidants reduces scarring and normalizes blood coagulation during therapy.
The present invention is directed to an improved delivery device and method for the transdermal administration of various therapeutic agents, including therapeutic agents useful in the various phases of wound healing, such as ascorbic acid. The device incorporates the use of mechanical or vibrational energy (most preferably ultrasound), light therapy (most preferably near-infrared light therapy), and heat and/or cold therapy as part of the wound healing process.